The overall objective of the current research is to investigate the psychological aspects of REM sleep and dreaming. Recently, we have utilized the REM deprivation strategy, awakening subjects at the onset of each REM period occurring during a specified period of the night. The psychological aspect of REM may be studied in at least two ways: (1) investigating the influence of psychological factors in modifying REM drive; (2) investigating the effect of REM deprivation on post-sleep behavior. For example, we have experimentally manipulated the cognitive activity of subjects during 5 minute awakenings used to REM deprive them, and found that for females at least, REM antithetical cognitive activity increased the drive for REM beyond expected values. However, we were not able to show that REM-congruent cognitive activity was able to reduce REM pressure. Our most recently completed study explored the effect of pre-sleep stress on deprivation-induced REM drive, and the effect of REM deprivation on post-sleep behavior. The study was designed to assess the validity of the assumption that (a) REM sleep contributes to either new learning or emotional adaptation, and (b) this function is reflected both in REM drive and post-deprivation behavioral effects. Our current study is designed to test the effect of immediate vs. delayed, and partial vs. total REM deprivation on the learning and memory of easy vs. difficult ("prepared" vs. "unprepared") verbal material. Finally, we are on the verge of carrying out some preliminary pilot work on experimentally influenced dreaming and its effect on post-sleep behavior.